Study of the degradation of the herbicide clomazone in distilled and in irrigated rice field waters using HPLC-DAD and GC-MS

• Autor(a) principal: Zanella,Renato
• Data de Publicação: 2008
• Outros Autores: Primel,Ednei G., Gonçalves,Fábio F., Martins,Manoel L., Adaime,Martha B., Marchesan,Enio, Machado,Sérgio L. O.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532008000500026
• topic: clomazone; degradation; HPLC-DAD; GC-MS; water

This study evaluated the degradation of the herbicide clomazone in distilled water and from irrigated rice fields, through UV irradiation and under natural conditions. After a solid phase extraction (SPE) as preconcentration step, the remained concentration of clomazone was determined by high performance liquid chromatography with diode array detection (HPLC-DAD) and the identification of the degradation products was achieved by gas chromatography-mass spectrometry (GC-MS). Under UV irradiation, the clomazone was degraded faster in distilled water than in surface water. In irrigated rice water, under sunlight irradiation, clomazone presented a half-life time average of 3.2 days in three consecutive harvests, and after application the concentration in water remained higher than 0.1 μg L-1 for 20 days. Several by-products, like 2-chlorobenzaldehyde and 2-chlorobenzene methanol, were identified by GC-MS, which evidenced that the concentration of intermediates at the begining increase and then they also undergo degradation.